Phase-shifting system and antenna field comprising such a phase-shifting system

ABSTRACT

A phase-shifting system for electrically swiveling the direction of a beam of an antenna field includes several radiators with two planes of polarization. The phase-shifting system includes two jointly changeable phase shifters with microstrip lines associated therewith. The electrical length of each phase shifter can be changed by a dielectric which is slidable above the microstrip lines. Such a phase-shifting system offers a simplified design and added functional safety by arranging the microstrip lines of both phase shifters in parallel next to each other and by providing a common slidable dielectric in order to change the electrical length of the microstrip lines of both phase shifters.

TECHNICAL FIELD

The present invention relates to the field of radiofrequencyengineering. It relates to a phase shifter arrangement according to thepreamble of claim 1 and an antenna array having such a phase shifterarrangement according to the preamble of claim 17.

Such a phase shifter arrangement or such an antenna array is disclosed,for example, in the document US-B1-6,310,585.

PRIOR ART

In mobile radio technology, antenna arrays or antennas, in which two ormore individual radiators are arranged one behind the other in amounting direction and are driven via a common supply network, have longbeen known for equipping the base stations. In order to be able to takebetter account of the different conditions at the location of therespective base station and of the interaction with other base stations,it has proved to be advantageous to provide the antennas with thepossibility of a “down tilt”. This may take place, in principle, bypurely mechanical means by the antenna being designed such that it canbe adjusted at the point at which it is fixed to the mast. Onedisadvantage of this is the fact that considerable complexity isrequired to adjust and alter such a mechanical down tilt and it isusually necessary to climb the mast for this purpose.

Several suggestions have therefore been made to carry out an “electricaldown tilt” by, in the case of a fixed antenna, the individual radiatorsof the antenna or the antenna array being driven on different phasessuch that the radiation lobe formed by superimposing the phase-shiftedarrays of individual radiators is tilted in a desired manner (“phasedarray”). Examples of such an electrical “down tilt” are disclosed inU.S. Pat. No. 6,198,458 or in U.S. Pat. No. 5,801,600 or in U.S. Pat.No. 5,905,462. Used here are special differential phase shifters (seealso DE-A1-199 11 905 or U.S. Pat. No. 5,949,303) or other phaseshifters which are arranged in the supply network of the antenna betweenthe individual radiators and can be adjusted at the same time, forexample, via a linkage by means of a motor drive (see also U.S. Pat. No.5,798,675). The simple, electrically controllable adjustability in thiscase also provides the possibility of remote adjustment from a controlcenter or the like (“remote tilt control”).

Combinations of mechanical and electrical down tilts are likewiseconceivable (U.S. Pat. No. 5,440,318).

In more recent mobile radio transmission methods having a high datatransmission rate, as are known, for example, by the abbreviation UMTS,the transition is increasingly being made to using “dual polarizedantennas” in order to be able to make use of the effect of “polarizationdiversity” in which multiple transmission of data is possible on radiowaves having a different polarization for the purpose of increasingtransmission reliability. The radiators in these antennas in this caseeach have two radiator elements for the two polarizations and are in theform of, for example, cruciform dipoles or correspondingly designedpatch radiators.

The document U.S. Pat. No. 6,310,585 mentioned initially has alsoalready proposed an electrically controlled down tilt by means of phaseshifters for the dual polarized antennas or antenna arrays. For thispurpose, each of the two radiator elements of a radiator within thesupply network has in each case one associated phase shifter (40 in FIG.1; 440 in FIG. 3), in which, for example, a microstrip line isoverlapped to a greater or lesser extent by a displaceable dielectric(column 3, lines 61-65; column 5, lines 1-18). Details on the phaseshifters and the associated microstrip lines are not given in thedocument.

In U.S. Pat. No. 6,310,585, the phase shifters for all of the radiatorelements of one polarization direction are rigidly coupled mechanicallyto one another by means of a first rod. The phase shifters for all ofthe radiator elements of the other polarization direction are likewiserigidly coupled to one another mechanically by means of a second rod.The two rods, for their part, are rigidly connected to one another bymeans of a central supporting device (415 in FIG. 3) and are driven by apinion via a toothed rack. In addition, two or more flexible positioningelements (420 in FIG. 3) are provided which press the dielectric againstthe microstrip lines below.

Disadvantages of this known phase shifter arrangement are not only thecomplex displacement mechanism comprising a plurality of individualelements, but also the separate structure of the individual phaseshifters which requires high accuracy on assembly and thus increasedmounting complexity with, at the same time, increased susceptibility tofaults.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to develop a phase shifterarrangement of the type mentioned initially such that the disadvantagesof the known phase shifter arrangements are avoided, and such that, inparticular, the design is simplified and the desired functionality isreliably achieved, as well as to specify an antenna array having such aphase shifter arrangement.

The object is achieved by all of the features of claims 1 and 17. Thecore of the invention consists in arranging the microstrip lines of thetwo phase shifters parallel and next to one another, and in providing acommon, displaceable dielectric for the purpose of altering theelectrical length of these microstrip lines of the two phase shifters.In this manner, only a single displaceable dielectric is required perradiator, and this may be used to automatically and synchronously adjustthe electrical length for the two polarizations. There is thus also onlya single row of dielectrics arranged one behind the other provided inthe mounting direction of the antenna array, and this row of dielectricsmay be displaced at the same time in a particularly simple manner bymeans of a single rod extending in the longitudinal direction.

In particular, the microstrip lines and the displaceable arrangement ofthe dielectric are designed such that the electrical length of the twoparallel microstrip lines is altered to the same extent when thedielectric is displaced. This ensures that the radiation lobe always hasthe same orientation for the two polarizations.

In principle, it would also be conceivable to displace the dielectricsof the phase shifter arrangements transversely with respect to themounting direction of the antenna array. However, particularly simple isthe mechanical system whereby, according to a preferred refinement ofthe invention, the microstrip lines extend essentially along alongitudinal axis, and the dielectric can be displaced in the directionof the longitudinal axis.

The microstrip lines preferably each have at least one center piecewhich is completely overlapped by the displaceable dielectric in a firstposition and is left completely free in a second position. In this case,it is favorable for the setting characteristics if the microstrip linesin the center pieces run transversely with respect to the longitudinaldirection and have a meandering structure, since the electrical lengthis thus altered to a greater extent per unit of the displacement path.

Already disclosed in U.S. Pat. No. 3,656,179 is a way of altering theassociated characteristic impedance by displacing the dielectric in abus strip arrangement. In order to reduce the degree of alteration tothe characteristic impedance to a tolerable level, another refinement ofthe invention provides for two or more line sections running parallel inthe longitudinal direction to be provided within the meanderingstructure, and for the microstrip lines to alter their strip width inthe line sections running in the longitudinal direction.

The alteration to the strip width is preferably designed such that, whenthe dielectric is displaced from the second to the first position, thestrip width of the overlapped line sections, starting from a minimumstrip width, increases as the overlap increases up to a maximum stripwidth, in particular the strip width increasing linearly with thedisplacement path in the longitudinal direction.

Particularly advantageous variation of the characteristic impedance byan average value results when the minimum strip width is selected suchthat, when there is an overlap with the dielectric in the region of theminimum strip width, the same characteristic impedance of the microstriplines is produced as in the region of the maximum strip width wherethere is no overlap with the dielectric. This type of alteration to thestrip width is advantageous for each phase shifter which operates withthe displacement of a dielectric above a microstrip line, andspecifically independently of whether two or more phase shifters have acommon dielectric or not.

In addition, adjusting pieces having a differing strip width can bearranged in the line sections running in the longitudinal direction forthe purpose of adjusting the characteristic impedance.

The phase shifter arrangement according to the invention is simplifiedfurther if the microstrip lines of the two phase shifters are arrangedand formed on a common printed circuit board. Together with the common,displaceable dielectric, there is thus a high degree of synchronizationwith, at the same time, a particularly simple design.

One possible refinement of the printed circuit board consists in themicrostrip lines of the two phase shifters being designed to bemirror-symmetrical with respect to a center axis, running parallel tothe longitudinal axis, of the printed circuit board.

In order for the displaceable dielectric to always be in a definedposition relative to the microstrip lines below, it is advantageous ifthe microstrip lines of the two phase shifters and the common dielectricabove are pressed flat against one another by means of a spring metalsheet.

A particularly uniform pressing action results when the spring metalsheet is arranged on the underside of the microstrip lines and iselectrically insulated from the microstrip lines by means of anintermediate insulating plate, and if the spring metal sheet has aplurality of individual spring tongues distributed over its surface.

Provided for the drive of the phase shifter is preferably a slide whichis guided displaceably in the longitudinal direction, can be actuatedmanually from the outside or using a motor, and is in engagement withthe dielectric. This configuration is particularly simple andfunctionally reliable and has the advantage of retaining its positionwhen the motor drive fails.

It has proven successful in practice to use a plate having a relativedielectric constant of approximately 10, in particular in the form of aglass fiber-reinforced, organoceramic laminate, as the dielectric.

A preferred refinement of the antenna array according to the inventionis characterized in that two or more phase shifter arrangements whichcan be displaced at the same time are arranged one behind the otherwithin the supply network, and in that connections are provided betweenand downstream of the phase shifter arrangements for the purpose ofconnecting the radiators.

Another preferred refinement is distinguished by the fact that radiatorsare arranged in the antenna array 2n+1 (n=1, 2, 3, . . . ), that 2nphase shifter arrangements are arranged one behind the other in theassociated supply network, that the supply inputs are connected to thesupply network between the n-th and the (n+1)-th phase shifterarrangement, and that all of the phase shifter arrangements can beactuated at the same time, the first n phase shifter arrangementsoperating in opposition to the second n phase shifter arrangements.

Further embodiments are described in the dependent claims.

BRIEF EXPLANATION OF THE FIGURES

The invention will be explained in more detail below with reference toexemplary embodiments in connection with the drawing, in which:

FIG. 1 shows a cross section (FIG. 1A), a plan view from above (FIG. 1B)and a longitudinal section (FIG. 1C) through an individual phase shifterarrangement comprising two phase shifters according to a preferredexemplary embodiment of the invention;

FIG. 2 shows the base plate of the phase shifter arrangement shown inFIG. 1;

FIG. 3 shows an insulating film of the phase shifter arrangement shownin FIG. 1;

FIG. 4 shows a plan view (FIG. 4A) and a side view (FIG. 4B) of thespring metal sheet of the phase shifter arrangement shown in FIG. 1;

FIG. 5 shows an insulating plate of the phase shifter arrangement shownin FIG. 1;

FIG. 6 shows the printed circuit board having the two microstrip linesof the phase shifter arrangement shown in FIG. 1;

FIG. 7 shows the dielectric of the phase shifter arrangement shown inFIG. 1;

FIG. 8 shows a plan view from above (FIG. 8A) and a side view from thefront (FIG. 8B) of the slide of the phase shifter arrangement shown inFIG. 1;

FIG. 9 shows the plan view of two sides (FIGS. 9A and B) of a printedcircuit board having 8 phase shifter arrangements according to theinvention for an antenna array having in total 9 radiators; and

FIG. 10 shows the simplified circuit diagram for the antenna array shownin FIG. 9.

WAYS OF IMPLEMENTING THE INVENTION

FIG. 10 shows the simplified circuit diagram of an antenna array 105, inwhich the present invention can advantageously be used. The antennaarray comprises in total 9 radiators 106, . . . , 114, which arearranged one behind the other (one on top of the other) in a (vertical)mounting direction. Each of the radiators 106, . . . , 114 comprises twoindividual radiator elements 106 a, b (the reference numerals for theradiator elements in the radiators 107, . . . , 114 are omitted forclarity). Each of the radiator elements 106 a, b is associated with onepolarization direction. The two polarization directions are generally atright angles to one another and usually form an angle of 45° with themounting direction of the antenna array 105. The radiators 106, . . . ,114 are provided both for emitting and receiving radio waves.

The radiators 106, . . . , 114 or radiator elements 106 a, b areconnected, via a supply network 115, to two supply inputs 99 a, b, whichare arranged within the supply network 115 at the level of the centralradiator 110. Each of the two supply inputs 99 a, b is assigned one ofthe polarization directions and is connected to the correspondingradiator elements. In order for the radiators 106, . . . , 114 to beable to form a “phase array” and to emit and receive an electricallypivotable beam, phase shifters 91 a, b, . . . , 98 a, b, are arranged inpairs distributed in the supply network 115. Each pair of phase shifters91 a, b, . . . , 98 a, b forms a phase shifter arrangement. The twophase shifters of a pair of phase shifters or of a phase shifterarrangement are adjusted in synchrony, as is illustrated in FIG. 10 bythe dashed connecting lines within each pair. All of the phase shifterpairs 91 a, b, . . . , 98 a, b are actuated at the same time by aconnecting tongue 116 running in the longitudinal direction (mountingdirection), which is driven manually or using a motor and is likewiseillustrated using dashed lines in FIG. 10. The change in the phase shiftin the phase shifters 95 a, b, . . . , 98 a, b arranged below the supplyinputs 99 a, b takes place in this case in opposition to the change inthe phase shift in the phase shifters 91 a, b, . . . , 94 a, b arrangedabove the supply inputs 99 a, b (i.e. an increase in the phase shift atthe bottom corresponds to a decrease in the phase shift at the top, andvice versa), which is indicated in FIG. 10 by the arrows in the phaseshifters having a different orientation.

The central one of the 9 radiators 106, . . . , 114, namely the radiator110, is connected directly to the supply inputs 99 a, b and thusoperates on a constant phase. The remaining 8 radiators 106, . . . , 109and 111, . . . , 114 each have an associated phase shifter pair. Sincethe phase shifter pairs 91 a, b, . . . , 98 a, b are connected in serieswithin the supply network 115, the individual phase shifts, startingfrom the center, are summed. If all of the phase shifters are the same,the phase shift toward the outside increases in equal increments: thesignal supplied to the supply inputs 99 a, b reaches the radiator 109with a single phase shift, the radiator 108 with a dual phase shift, theradiator 107 with a triple phase shift, and the radiator 106 with aquadruple phase shift. The same applies for the radiators 111 to 114.

A single phase shifter pair or a single phase shifter arrangement nowpreferably has a construction as is shown in the exemplary embodiment inFIGS. 1 to 8, in which, in FIG. 1, different views are depicted of acompletely assembled arrangement, whereas FIGS. 2 to 8 show theindividual elements of the arrangement shown in FIG. 1 in sequencewithin the arrangement. The printed circuit board 60 shown in FIG. 6 andhaving the microstrip lines 66, 67 in this case only represents thesubsection of a longer printed circuit board 90, as is reproduced inFIG. 9 for the entire antenna array 105 shown in FIG. 10.

The printed circuit board 60 (FIG. 6), which is made of, for example, abase material of 0.5 mm in thickness having a double-sided 35 μm Cucoating, has, on the underside, a continuous Cu coating and, on the topside, the conductor tracks shown which are mirror-symmetrical withrespect to a center axis 11 and form the microstrip lines 66, 67. Theprinted circuit board 60 is arranged in the phase shifter arrangement 10in FIG. 1 between a (lower) base plate 20 (FIG. 2) and an (upper) slide80 (FIG. 8) such that the conductor tracks of the microstrip lines 66,67 are on the side of the slide 80. The base plate 20, which may be inthe form of, for example, an aluminum plate, has, on the sides, twofastening tabs 21, 22 having corresponding fastening holes 23, 24, bymeans of which it can be screwed tightly to an antenna housing.

The printed circuit board 60 is fixed in relation to the base plate 20.This is achieved by two lugs 25, 26 which engage in correspondingopenings 64, 65 in the printed circuit board 60 (FIG. 6) being bent backupward at right angles on the base plate 20. Also provided in theprinted circuit board 60 are three guide openings 61, . . . , 63 in theform of slots which are spaced apart from one another, run parallel tothe center axis 11, and in which the slide 80 engages withcorrespondingly formed and arranged engaging cams 81, . . . , 83 (FIG.1; FIG. 8). The guide openings 61, . . . , 63 determine the displacementregion of the slide 80 relative to the printed circuit board 60.

The slide 80, which may be made of, for example, plastic and may be aninjection-molded part, also has two lateral guides 86, 87 which engageover the lateral edge of the printed circuit board 60. On its top sideof the slide 80, integrally formed in a depression and one behind theother in the longitudinal direction, are two driver cams 88, 89 withwhich an actuating element (not shown) for the slide can engage.Furthermore, two recesses 84, 85 are provided on the slide 80 in orderto provide space for the lugs 25, 26 protruding through the printedcircuit board 60 from below.

The actual phase shifters 10 a, 10 b of the phase shifter arrangement 10are formed by the interaction of the microstrip lines 66, 67 with adielectric 70 arranged displaceably on the top side of the printedcircuit board 60. The dielectric 70 shown in detail in FIG. 7 comprises,for example, an organoceramic laminate of the CER-10 type, as can beprocured from the US company Taconic, Petersburgh, N.Y. (USA). The glassfiber-reinforced laminate filled with ceramic has a dielectric constantof 10 and very good mechanical properties. A plate of this material isused having a thickness of approximately 0.64 mm. Other dielectrics arealso conceivable, however. According to FIG. 7, the dielectric 70 hasthree circular engaging openings 71, . . . , 73 which are spaced apartfrom one another and in which the slide 80 engages with its engagingcams 81, . . . , 83. The dielectric 70 is thus fixed in relation to theslide 80 and is displaced along with the slide 80. Furthermore, tworecesses 74, 75 are provided in the dielectric 70 which are comparablein shape and function to the recesses 81, 82 of the slide 80.

The interaction of the microstrip lines 66, 67 and the dielectric 70takes place essentially in the region of the meandering center pieces 66b, 67 b of the microstrip lines 66, 67 which are each arranged betweenconnection pieces 66 a, c and 67 a, c and run transversely with respectto the center axis 11 (FIG. 6). Each of the center pieces 66 b, 67 bcomprises two or more (in the example in FIG. 6, 5) line sections 66 d,. . . , h, which run parallel to the center axis 11 and are connected toone another for the purpose of forming the meandering pattern onalternating sides by means of U- or V-shaped bent pieces. Within theline sections 66 d, . . . , h, the line width varies linearly withrespect to the length and in the process decreases from left to right.Since the dielectric 70 with its left-hand edge moves when beingdisplaced precisely in the region of the line sections 66 d, . . . , h,when the dielectric is displaced, regions of the line sections 66 d, . .. , h having different line widths are covered or not covered.

There is a particular reason for the variation in the line width of theline sections 66 d, . . . , h: In order to maintain the (conventional)characteristic impedance of the microstrip lines 66, 67 of 50 ohms, theline width in the case of the materials and dimensions used isapproximately 1.5 mm (without a dielectric on top). In the region of thedielectric on top, however, only a line width of approximately 0.98 mmis required for a characteristic impedance of 50 ohms owing to thedielectric. Therefore, if the line width outside the region of coverageof the dielectric is set at 1.5 mm and at 0.98 mm in the region ofcontinuous coverage and a linear transition between these two extremevalues is assumed in the intermediate line sections 66 d, . . . , h, thedeviation of the actual characteristic impedance when the dielectric 70is displaced varies by the average value of 50 ohms, the characteristicimpedance being more than 50 ohms if the dielectric 70 is shifted to theleft far beyond the line sections 66 d, . . . , h, and being less than50 ohms if the dielectric 70 is shifted only slightly beyond the linesections 66 d, . . . , h. Since only the absolute value of thedifference is relevant for the (undesired) erroneous adjustment, and notthe mathematical sign, a larger displacement region of the dielectricand thus a larger phase shift over a larger frequency range can thus beobtained utilizing the maximum permissible erroneous adjustment. Inaddition, it is possible for the electrical properties to be optimizedby adjusting pieces 68, 69 being provided which are wider in the centerpieces 66 b, 67 b (FIG. 6).

The two microstrip lines 66, 67 are (as can easily be seen in FIG. 6)formed and arranged such that they are mirror-symmetrical with respectto the center axis 11. The dielectric 70 is selected to be so wide that,in the event of a displacement in the direction of the center axis 11,the meandering center pieces 66 b, 67 b of the microstrip lines 66, 67are overlapped or left free in the same manner. This makes it possible,without high complexity and with functional reliability to achievesynchronization between the two phase shifters 10 a and 10 b and to makethe phase shifts in the two phase shifters 10 a, b largely uniform.

However, an essential element ensuring functional reliability is thefact that the dielectric 70 bears tightly against the surface of theprinted circuit board 60 carrying the microstrip lines 66, 67, ifpossible without an air gap. This is achieved by means of a flat springmetal sheet 40 (FIGS. 4A, B) which is arranged between the base plate 20and the printed circuit board 60 and presses the printed circuit board60 from below against the dielectric 70 held in the slide 80. The springmetal sheet 40 has (as does the base plate 20) lateral fastening tabs41, 42 having corresponding fastening holes 43, 44 which are alignedwith the fastening holes 23, 24 in the base plate 20. Arrangeddistributed over the surface of the spring metal sheet 40 is, next toone another, a large number of individual spring tongues 45 which havebeen produced, for example, from the spring metal sheet 40 by a stampingor bending process. The spring metal sheet 40 is electrically insulatedfrom the base plate 20 by means of an intermediate, thin insulating film30 (FIG. 3) which matches the base plate 20 and the spring metal sheet40 in terms of the lateral fastening tabs 31, 32 and fastening holes 33,34. The spring metal sheet 40 is furthermore electrically insulated withrespect to the lower Cu layer of the printed circuit board 60 by meansof an intermediate, for example 0.5 mm thick, insulating plate 50 (FIG.5), against which the spring tongues 45 press. The insulating plate hasopenings 54, 55, through which the lugs 25, 26 of the base plate 20 passthrough for fixing purposes. The slot-like guide openings 51, . . . , 53are analogous to the guide openings 61, . . . , 63 in the printedcircuit board 60 in terms of function and shape.

The exemplary embodiment shown in FIGS. 1 to 8 relates only to a phaseshifter arrangement comprising two phase shifters 10 a, b which iscorrespondingly only suitable for adjusting a dual polarized radiator.If, as is shown in FIG. 10, an antenna array 105 comprises more thantwo, for example 9, radiators 106, . . . , 114, and two or more, in theexample 8, phase shifter arrangements are required for electricallypivoting the antenna beam, these phase shifter arrangements, togetherwith the supply network 115, are preferably integrated on a singleprinted circuit board. Such a printed circuit board 90 for in total 9radiators and 8 phase shifter arrangements is reproduced in FIG. 9.Formed on this printed circuit board 90 are, mirror-symmetrically withrespect to the center axis 11, two microstrip lines 90 a, b havingbranches which at the same time form a supply network with the powerdistributed over two or more antenna connections 102 a, b, . . . , 104a, b (for simplicity only the antenna connections for 4 radiators areprovided with reference numerals in FIG. 9B; in total there are antennaconnections for 9 radiators or 18 radiator elements).

Formed within the supply network of the microstrip lines 90 a, b are, inanalogy to FIG. 6, meandering center pieces 91 a, b, . . . , 98 a, bwhich are each part of a phase shifter arrangement 91, . . . , 98comprising two phase shifters. The supply inputs 99 a, b are arranged inthe center of the printed circuit board 90. Each of the phase shifterarrangements 91, . . . , 98 is assigned (in analogy to FIGS. 1 to 8) adielectric which can be displaced by means of a slide, a base plate, anda spring metal sheet which is mounted such that it is insulated.Correspondingly, in each of the phase shifter arrangements 91, . . . ,98, guide openings 100 and openings 101 are provided for engagement ofthe base plate. The (nine) slides of all of the phase shifterarrangements 91, . . . , 98 are in engagement with a common actuatingelement (not shown) which extends along the center axis 11 over theentire printed circuit board 90 and can be displaced in the longitudinaldirection manually from the outside or by means of a controlled motordrive.

In Summary the Following can be Said:

Phase shifters are required to achieve a variable down tilt in the caseof an antenna array. It must be possible for the main lobe of theantenna to be lowered beyond the horizontal at least to a first zeroposition. In mobile radio engineering (GSM, UMTS), it is necessary tofulfill the following requirements:

In the case of large antennas, it must be possible to alter the downtilt between 0° and approximately 8°; for this purpose, it must bepossible for the phase to be altered continuously between 0° andapproximately 45° by means of the phase shifter.

In the case of small antennas, it must be possible to alter down tiltbetween 0° and approximately 16°; for this purpose, it must be possiblefor the phase to be altered continuously between 0° and approximately85° by means of the phase shifter.

There are several possible ways of altering the phase. The followingrelationship applies between the electrical and the mechanical length ofa line:I _(elec) =I _(mech){square root}{square root over (ε_(r))}

The electrical length is proportional to the phase:$\varphi = {\frac{I_{elec}}{\lambda}360{^\circ}}$

In order to alter the phase, the mechanical length or the ε_(r) can bealtered.

A patent has already been applied for by the applicant for a phaseshifter with means for altering the mechanical length of the line.

A phase alteration by altering the ε_(r) can be achieved in the case ofa microstrip line by a dielectric being laid on the line (see DE-A1-19911 905).

According to the present solution, two or more line sections lyingparallel and next to one another are connected to one another by a 180°corner to form a meandering structure. A dielectric having a high ε_(r)is pushed over this line structure, a common dielectric being used fortwo adjacent phase shifters. The maximum possible phase shift is givenby the number of line sections and their length which at the same timecorresponds to the displacement path of the dielectric.

Using 5 parallel line sections, a phase shift of 46° is achieved; with 7parallel line sections, a phase shift of 65° is achieved. In order toachieve an even greater phase shift, two or more phase shifters can beconnected one behind the other.

By using an uneven number of line sections lying parallel and next toone another, the phase shifter can be integrated very effectively in asupply network. However, the phase shifter may also be realized using aneven number of lines, which may be more advantageous for otherapplications.

Each individual line section in the phase shifter has a line width whichcan be altered linearly (is linearly tapered). In the 0° position of thephase shifter (the dielectric is not over the line sections), the linewidth is narrower and is of such a width that, together with thedielectric pushed on top of it, the system impedance (50 Ω) is given. Atthe other end of the line sections, the line width corresponds to thenormal microstrip. Despite the tapered line sections, depending on theposition of the displaceable dielectric, there is an erroneousadjustment. Erroneous adjustment may be compensated for by smalladjusting pieces (“stubs”) in the line structure.

The phase shifter operates as follows: a base plate made of aluminum isscrewed onto the antenna housing and positions, by means of twobent-back lugs, the printed circuit board having the line structure. Thedisplaceable dielectric is located on the printed circuit board. Betweenthe aluminum plate and the printed circuit board is a spring metal sheetwhich presses the printed circuit board against the dielectric. Theprinted circuit board (ground), the spring metal sheet and the aluminumplate are insulated from one another by additional insulators.

It is possible to use a substrate having a high ε_(r) as the dielectric.This thin platelet is held by an additional plastic part (slide), whichalso has driver cams for the slide apparatus. It is also possible, byselecting a suitable plastic or a ceramic, for the dielectric plateletand the plastic part to be integral.

The phase may be set by means of a manually or electrically operateddrive.

List of Reference Numerals

-   10 Phase shifter arrangement-   10 a, b Phase shifter.-   11 Center axis-   20 Base plate-   21, 22 Fastening tab-   23, 24 Fastening hole-   25, 26 Lugs-   30 Insulating film-   31, 32 Fastening tab-   33, 34 Fastening hole-   40 Spring metal sheet-   41, 42 Fastening tab-   43, 44 Fastening hole-   45 Spring tongue-   50 Insulating plate-   51, . . . , 53 Guide opening (slot)-   54, 55 Opening-   60 Printed circuit board-   61, . . . 63 Guide opening (slot)-   64, 65 Opening-   66, 67 Microstrip line-   66 a, 67 a Connection piece-   66 b, 67 b Center piece (meandering)-   66 c, 67 c Connection piece-   66 d, . . . , h Line section-   68, 69 Adjusting piece-   70 Dielectric-   71, . . . , 73 Engaging opening-   74, 75 Recess-   80 Slide-   81, . . . , 83 Engaging cams-   84, 85 Recess-   86, 87 Lateral guide-   88, 89 Driver cams-   90 Printed circuit board-   90 a, b Microstrip line-   91, . . . , 98 Phase shifter arrangement-   91 a, b, . . . , 98 a, b Phase shifter (center piece)-   99 a, b Supply input-   100 Guide opening-   101 Opening-   102 a, b, . . . , 104 a, b Antenna connection-   105 Antenna array-   106, . . . , 114 Radiator-   106 a, b Radiator element-   115 Supply network-   115 a, b Branch (supply network)-   116 Connecting tongue

1-20. (canceled)
 21. A phase shifter arrangement for electricallypivoting the irradiation direction of an antenna array which includestwo or more radiators having two polarization planes, the phase shifterarrangement comprising two phase shifters which can be altered at thesame time, having associated microstrip lines whose electrical lengthcan in each case be altered by means of a dielectric which is arrangedsuch that it can be displaced over the microstrip lines, wherein: themicrostrip lines of the two phase shifters are arranged parallel andnext to one another; and a common, displaceable dielectric is providedfor the purpose of altering the electrical length of the microstriplines of the two phase shifters.
 22. The phase shifter arrangement ofclaim 21, wherein the microstrip lines and the displaceable arrangementof the dielectric are configured such that the electrical length of thetwo parallel microstrip lines is altered to the same extent when thedielectric is displaced.
 23. The phase shifter arrangement of claim 21,wherein the microstrip lines extend essentially along a longitudinalaxis, and the dielectric is displaceable in the direction of thelongitudinal axis.
 24. The phase shifter arrangement of claim 23,wherein the microstrip lines each has at least one center piece which iscompletely overlapped by the displaceable dielectric in a first positionand is left completely free in a second position.
 25. The phase shifterarrangement of claim 24, wherein the microstrip lines in the centerpieces run transversely with respect to the longitudinal direction andhave a meandering structure.
 26. The phase shifter arrangement of claim25, wherein: two or more line sections running parallel in thelongitudinal direction are provided within the meandering structure; andthe microstrip lines alter their strip width in the line sectionsrunning in the longitudinal direction.
 27. The phase shifter arrangementof claim 26, wherein, when the dielectric is displaced from the secondto the first position, the strip width of the overlapped line sections,starting from a minimum strip width, increases as the overlap increasesup to a maximum strip width.
 28. The phase shifter arrangement of claim27, wherein the strip width increases linearly with the displacementpath in the longitudinal direction.
 29. The phase shifter arrangement ofclaim 27, wherein the minimum strip width is selected such that, whenthere is an overlap with the dielectric in the region of the minimumstrip width, the same characteristic impedance of the microstrip linesis produced as in the region of the maximum strip width where there isno overlap with the dielectric.
 30. The phase shifter arrangement ofclaim 26, wherein adjusting pieces having a differing strip width arearranged in the line sections running in the longitudinal direction foradjusting the characteristic impedance.
 31. The phase shifterarrangement of claim 21, wherein the microstrip lines of the two phaseshifters are arranged and formed on a common printed circuit board. 32.The phase shifter arrangement of claim 31, wherein the microstrip linesof the two phase shifters are designed to be mirror-symmetrical withrespect to a center axis that runs parallel to the longitudinal axis ofthe printed circuit board.
 33. The phase shifter arrangement of claim21, wherein the microstrip lines of the two phase shifters and thecommon dielectric above are pressed flat against one another by means ofa spring metal sheet.
 34. The phase shifter arrangement of claim 33,wherein: the spring metal sheet is arranged on the underside of themicrostrip lines and is electrically insulated from the microstrip linesby means of an intermediate insulating plate; and the spring metal sheethas a plurality of individual spring tongues distributed over itssurface.
 35. The phase shifter arrangement of claim 21, wherein a slideis provided which is guided displaceably in the longitudinal direction,which can be actuated manually from the outside or using a motor, andwhich is in engagement with the dielectric.
 36. The phase shifterarrangement of claim 21, wherein a plate having a relative dielectricconstant of approximately 10 is used as the dielectric.
 37. An antennaarray comprising: a plurality of radiators which are arranged one behindthe other in a longitudinal direction, each of which includes tworadiator elements provided for different polarization planes, and whichare connected to two supply inputs via a supply network that includesphase shifter arrangements, each phase shifter arrangement comprisingtwo phase shifters which can be altered at the same time, havingassociated microstrip lines whose electrical length can in each case bealtered by means of a dielectric which is arranged such that it can bedisplaced over the microstrip lines, wherein: the microstrip lines ofthe two phase shifters are arranged parallel and next to one another;and a common, displaceable dielectric is provided for the purpose ofaltering the electrical length of the microstrip lines of the two phaseshifters.
 38. The antenna array of claim 37, wherein: two or more phaseshifter arrangements which can be displaced at the same time arearranged one behind the other within the supply network; and connectionsare provided between and downstream of the phase shifter arrangementsfor the purpose of connecting the radiator elements.
 39. The antennaarray of claim 38, wherein: radiator elements are arranged in theantenna array 2n+1 (n=1, 2, 3, . . . ), 2n phase shifter arrangementsare arranged one behind the other in the associated supply network; thesupply inputs are connected to the supply network between the n-th andthe (n+1)-th phase shifter arrangement; and all of the phase shifterarrangements can be actuated at the same time, the first n phase shifterarrangements operating in opposition to the second n phase shifterarrangements.
 40. The antenna array of claim 37, wherein the supplynetwork and the phase shifter arrangements are arranged on a commonprinted circuit board.